Winter 2018Rebuild

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MickeyMoto
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Winter 2018Rebuild

Post by MickeyMoto »

Picked up a Sport 3FD for restoration. Two weeks in and stripping down coming along nicely.

Top photo is not the 3FD...
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MickeyMoto
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Re: Winter 2018Rebuild

Post by MickeyMoto »

Silly question time.

Before I attack the primary drive, is the nut on the end of the crankshaft left or right hand thread? I have assumed right as nowt in the manual to say otherwise... :)

Any tips to get it off? One magazine says use a mandrel through the small end and pieces of wood across the crankcase mouth! Doesn't sound correct to me. I have the holding tool and the peg socket.

Thanks,

Mike.
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72degrees
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Re: Winter 2018Rebuild

Post by 72degrees »

Right hand thread but effing tight.

I had the cases on the bench positioned so that the holding tool was clamped in a vice and then used a breaker bar for the socket.
That was with the old style hex head nut though so a nice surface drive socket could be used. I also used a bit of judicious heat and Plusgas first.

It will be a good test of the quality of the peg socket.

Reassembly is the reverse of disassembly but I still struggled a bit even with the holding tool and a peg socket to tighten the new style nut up to the required torque (let's not get in to exactly what that is again yet - you can ask later ;) ).
MickeyMoto
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Re: Winter 2018Rebuild

Post by MickeyMoto »

Thank you.

I might put the remains back in the frame to hold the cases still. I think I need a long bar...
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72degrees
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Re: Winter 2018Rebuild

Post by 72degrees »

MickeyMoto wrote:Thank you.

I might put the remains back in the frame to hold the cases still. I think I need a long bar...
Sounds like a good plan. It reminds me of the first time I changed the rear sprocket on the GFR and had to undo the nut on the dummy spindle (single sided swing arm). The force applied by the breaker bar was sufficient to compress the monoshock spring and lift the back of the bike in to the air, even with my puny muscles. I tried a rattle gun to no avail (as I also did on the primary gear nut - though I wouldn't recommend it when using a peg socket). There wasn't room to put the bar on the other way round and stand on the end ( a useful technique when undoing car wheel nuts with a standard toolkit). I did try a very strong T-Bar and a lump hammer but room to get a good downward swing was limited. After several heat/Plusgas cycles it eventually succumbed to the breaker bar with the lad applying his weight to the frame of the bike. Not with a sudden failure as feared but just gently moved a bit.

The mandrel through the small end blocked on the crankcase mouth with timber can be successful - but you have to have a well fitting mandrel of the correct length (unless the small end bushes or rods are being changed so any 'bruising' isn't an issue. I tried it on my strip down using a small diameter rod (like using a pin puller) through a gudgeon pin, as I knew I was replacing the pistons. I only succeeded in starting to gouge the mandrel in to the pieces of blocking timber.

If at first you don't succeed...
'It must be a .....'
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Re: Winter 2018Rebuild

Post by 'It must be a .....' »

Hi, right hand thread and the ring nut is usually very tight and needs a lot of force to get it moving.

Having an engine out on the bench and no access to a holding tool, last weekend I used a cheap electric impact wrench and it was so easy; just holding the gear with a Boa Constrictor grip (rubber strap wrench).
But I will need to sort out a holding tool when I put it back together and tighten the ring nut with a torque wrench.

In the past I've always had the engine in a frame, crank holding tool attached to the frame and the special socket on a short extension which is supported (axle stand) so it won't slip off the ring nut when the pressure is put on the T bar with a fork leg.

Good luck
MickeyMoto
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Re: Winter 2018Rebuild

Post by MickeyMoto »

Yes, I was wondering about holding the socket when heaving...

Better get it done before the frame disappears for painting.
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72degrees
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Re: Winter 2018Rebuild

Post by 72degrees »

'It must be a .....' wrote:In the past I've always had the engine in a frame, crank holding tool attached to the frame and the special socket on a short extension which is supported (axle stand) so it won't slip off the ring nut when the pressure is put on the T bar with a fork leg.
Cunning.
SupermotoDave
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Re: Winter 2018Rebuild

Post by SupermotoDave »

If you have a spare primary drive you can drop that back on and lock the pair up using a penny(copyright MCM) or a cloth between the pair.
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72degrees
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Re: Winter 2018Rebuild

Post by 72degrees »

SupermotoDave wrote:If you have a spare primary drive you can drop that back on and lock the pair up using a penny(copyright MCM) or a cloth between the pair.
More cunning than a very cunning thing. I've tried it on some other similar scenarios on different engines and succeeded in only creating a new form of 'copper' jewellery.

I like the idea of using a fork leg to get even more leverage than a breaker bar. "Give me a lever long enough..."
MickeyMoto
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Re: Winter 2018Rebuild

Post by MickeyMoto »

So, engine in frame, frame tied down, holding tool resting on a block of wood. Heat applied,v600mm wrecking bar on the socket. Bent holding tool!

Maybe the impact wrench is the way to go. I'm changing the main bearings, just reluctant to put any force through the crank.

Just need to do this and the bits can go tongue painter, and I can start on the engine.
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72degrees
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Re: Winter 2018Rebuild

Post by 72degrees »

Crikey! Got to be worth trying the option of the impact wrench. In my experience whilst using one has never been an instant fix, it may soften things up a bit, so the next heat, plusgas, breaker bar sequence does the trick. I've never used one with a 'peg socket' though. I'd be concerened that the pegs would slip out of the slots or even braek off. A zip tie very tight round the socket and nut before rattle gunning might be the way to go. Having said that, tyre fitting bays use them all the time on locking wheel nut 'keys'.

After you have got that nut off and parted the cases (remember the dowels!) it sound like you may have a jolly game persuading the crank out of the primary side case main bearing. Have fun!
MickeyMoto
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Re: Winter 2018Rebuild

Post by MickeyMoto »

Thank you for the encouragement. One thing I need is time! Wanted to get the bits back for Christmas rebuild.
MickeyMoto
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Re: Winter 2018Rebuild

Post by MickeyMoto »

Success! All bits off both sides. All nuts loosened including the hidden ones! Just need a day to clean the parts and ready for painting.
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72degrees
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Re: Winter 2018Rebuild

Post by 72degrees »

MickeyMoto wrote:Success! All bits off both sides. All nuts loosened including the hidden ones! Just need a day to clean the parts and ready for painting.
Splendid. So did the impact wrench do the business?
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